VXI Variable Power On Configuration in Systems with PCIe Native Control

Publish Date: Mar 17, 2017 | 0 Ratings | 0.00 out of 5 | Print

Overview

Many computers that are running Windows have a feature enabled called PCI Express Native Control. When PCI Express Native Control is enabled it allows the use of certain features defined in the PCI Express Base Specification. More information on the features enabled by PCI Express Native Control can be found in the Microsoft Hardware Dev Center. Unfortunately, systems which have Native Control enabled may experience conflicts if the user tries to enable the NI-VXI Variable Power On (VPO) feature simultaneously.

Table of Contents

  1. Enabling the Variable Power On Function
  2. Re-Enabling PCI Express Native Control
  3. Potential Challenges When Enabling the Variable Power On Function
  4. Related Resources

1. Enabling the Variable Power On Function

The NI-VXI driver allows the user to power on and off the VXI chassis after powering on the host workstation, without having to power cycle, by enabling the VXI Variable Power On Function (VPO). The VPO function can be enabled through NI Measurement & Automation Explorer (MAX). 

The VPO function is not supported on systems that have PCI Express Native Control enabled. In order to use the VPO feature, the user will need to disable the PCI Express Native Control on the system with the following procedure:

  1. Open the Windows Command Prompt with administrative privileges. This can be done by searching Windows for 'cmd', right-clicking on the Command Prompt application, and selecting 'Run as Administrator'.
  2. Enter the following command: "bcdedit /set pciexpress forcedisable".
  3. Reboot the system.

 

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2. Re-Enabling PCI Express Native Control

PCI Express Native Control can be re-enabled by an administrative user by entering the following command at the Command Prompt: "bcdedit /set pciexpress default".

 

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3. Potential Challenges When Enabling the Variable Power On Function

In some cases enabling VPO can result in the system entering a state where Windows hangs during boot. If this occurs, the system can be restored through the following procedure:

  1. Power down the computer.
  2. Disconnect the MXI card from the PCIe slot on the computer's motherboard.
  3. Power the computer on. With the VXI hardware removed from the system, Windows should boot normally without hanging.
  4. Disable VPO through MAX.
  5. Power down the computer again.
  6. Reconnect the MXI card to the PCIe slot on the computer's motherboard and ensure all VXI hardware is connected normally.
  7. Power the computer on. With VPO disabled, Windows should boot normally without hanging.

 

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4. Related Resources

 

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